I need to create a secure web service on a server using IIS 6.0 and ASP.NET 2.0. I have Visual Studio 2008. I can create a file that is a Web Service file, and can define the interfaces for the client. What I don't know how to do is to authenticate the clients who invoke the interface. The website itself is secure (i.e. starts with https://
) I don't know what I need to do to authenticate the client. (Keep the IIS 6.0 and ASP.Net 2.0 restrictions in mind). Can someone please advise me on how to do this?